The objectives of this proposal are: (1) the preparation of kappa and delta selective ligands of suitable potency so that they can be employed in affinity chromatography to isolate and purify kappa and delta opioid receptors and (2) the preparation of a new type of photoaffinity label. The kappa ligands which we plan to prepare are related to tifluadom and the highly selective U-50488 and U- 69583. The photoaffinity labels are derived from photolabile substituted cyclohexadienones which can be coupled to derivatives related to such opiates as fentanyl and etonitazene.